[0/4] usercopy: generic tests + arm64 fixes

Message

Mark Rutland March 14, 2023, 11:50 a.m. UTC

This series adds tests for the usercopy functions, and fixes some
deficiencies on arm64.

This is a follow-up to Robin's earlier usercopy refresh [1], where we
found some issues and Will had asked for tests. In the process of
writing tests, I discovered arm64 had some latent issues, and running
the tests on other architectures, it looks like most have issues...

Al, I'd appreciate if you could take a look at the first couple of
patches and check if I've got the intended semantics correct. I think
I've got that right for __raw_copy_{to,from}_user(), but I'm not sure
whether clear_user() is expected to behave the same, and I may have
missed something or assumed something overly strong.

Catalin, Will, the last two patches fix arm64's implementation of
__raw_copy_to_user() and clear_user(), per the understanding above. I
believe these are correct (as they've passed exhaustive testing), and
benchmarking shows they're at least as good as the current
implementations. 

Thanks,
Mark.

[1] https://lore.kernel.org/linux-arm-kernel/[e-mail]/

Mark Rutland (4):
  lib: test copy_{to,from}_user()
  lib: test clear_user()
  arm64: fix __raw_copy_to_user semantics
  arm64: fix clear_user() semantics

 arch/arm64/lib/clear_user.S   | 195 ++++++++++---
 arch/arm64/lib/copy_to_user.S | 203 ++++++++++---
 lib/Kconfig.debug             |   9 +
 lib/Makefile                  |   1 +
 lib/usercopy_kunit.c          | 520 ++++++++++++++++++++++++++++++++++
 5 files changed, 848 insertions(+), 80 deletions(-)
 create mode 100644 lib/usercopy_kunit.c